[H0n3sty]

> First, ns-unmap your old name (a refactoring tool should do that for your, I guess).

clj-refactor has a cljr-rename-symbol function.

https://github.com/clojure-emacs/clj-refactor.el

Here's a full list of its features:

https://github.com/clojure-emacs/clj-refactor.el/wiki